It has become desirable for users of radiotelephones to replace a cover of the radiotelephone easily without requiring any special training or tools. Telephone handsets with exchangeable covers are known, e.g. from EP 1028574 A2. EP 1028574 A2 discloses a radio telephone comprising a front and a back cover. The radio telephone further comprises an inner housing retaining electronic components of the radiotelephone.
FIG. 1 shows a prior art radiotelephone 1 with a front cover 2, a back cover 3, an inner housing 4, and a keymat 5. To assemble the radiotelephone 1, the front and back covers 2, 3 are attached to mutual sides of the inner housing 4. The keymat 5 is sandwiched between the front cover 2 and the inner housing 4 such that keys 6 of the keymat 5 extend through holes 7 in the front cover 2 and, when a key is pressed, actuate key switches (not shown) on the inner housing 4. The main purpose of the keymat is to act as an interface between the user and the functions of the radiotelephone.
A problem with known technology is that a change of keymat require that the front cover is removed from the internal housing.
Another problem is that the front cover limits the freedom to design the keys of the keymat, since the keys have to fit the holes of the front cover.
U.S. 2003/0201983 discloses a keymat for use with a mobile station. The keymat includes a web for interconnecting a plurality of keys. The keymat is attached externally on a cover of the mobile station to permit a user to exchange the keymat for another. A plurality of key pins extends through openings in the cover of the mobile station. The keymat has retaining means for removably retaining the keymat to the mobile station. The retaining means are either key pins integrally formed with the keymat and extending inwardly through openings in the cover of the mobile station and provided with extensions on the key pins to engage the interior surface of the cover, or recesses in the keymat for receiving the key pins, or a slide plate disposed inward of the cover for engaging a keymat fixedly attached to a plurality of key pins that forms a recess for engaging the slide plate.
A problem with this solution is that the edges of the keymat is unprotected and not tightly attached to the cover, and may cause that the keymat is ripped off the cover during every day use, such as keeping the mobile station in a pocket or bag. Another problem with this solution is that attachment and removal are difficult. Further, a problem with this solution is that, when removing the keymat, the stress on the extensions for retaining the keymat many times will cause that the extensions are torn off, and it will not be possible to re-attach the keymat.